Methods of object search and recognition

ABSTRACT

Embodiments of the invention disclose techniques for processing of machine-readable forms of unfixed or flexible format. An auxiliary brief description may be optionally specified to determine the spatial orientation of the image. A method of searching for elements of a document comprises the following main operations in addition to the operations of preliminary image processing: selecting the varieties of structural description from several available variants, determining the orientation of the image, selecting the text objects, where the text must be recognized, and determining the minimal required volume of recognition, recognizing the text objects, searching for elements of the form. Searching for elements of the form comprises the following actions: selecting a searched element in the structural description, gaining the algorithm of search constraints from the structural description, searching for the element, testing the obtained variants.

FIELD

Embodiments of the present invention relate generally to imagerecognition and particularly to the recognition of non-text and/or textobjects contained in a bit-mapped image of a document.

BACKGROUND

A form is a structured document with one or more pages with fields to becompleted. Typically, each field has an associated label or inscriptionstating the nature of the data the field should contain.

Two types of forms can be identified—fixed forms and flexible forms. Afixed form has the same positioning and number of fields on all of itscopies and often has anchor elements (e.g. black squares or separatorlines), A non-fixed or flexible form may have different number of fieldswhich may be positioned differently from copy to copy. Examples offlexible forms include application forms, invoices, insurance forms,money order forms, business letters, etc.

Methods of structure assignment and document element search in anelectronic graphical image are described in U.S. Pat. No. 5,416,849 butare limited to processing only fixed forms with no deviation in fieldarrangement.

SUMMARY

Embodiments of the present invention disclose improvements in searchingcapabilities as well as the accuracy of identification of obtained imageobjects, as they applied to flexible or unfixed format forms based on aflexible document structure

Advantageously, the techniques disclosed herein have increased noiseimmunity during the process of object searching on flexible form images.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a flow chart of document of unfixed format processing.

FIG. 2 shows a flow chart of preliminary image processing.

FIG. 3 shows a flow chart of searching for elements of a form.

FIG. 4 shows a flow chart of testing the obtained variants.

FIG. 5 shows an example of a page of a document with non-fixed format.

FIG. 6 shows an exemplary hardware for implementing methods representedby flow charts shown in FIGS. 1-4, in accordance with an embodiment ofthe present disclosure.

DESCRIPTION

In the following description, for purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the invention. It will be apparent, however, to oneskilled in the art that the invention can be practiced without thesespecific details.

Reference in this specification to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least one embodimentof the invention. The appearances of the phrase “in one embodiment” invarious places in the specification are not necessarily all referring tothe same embodiment, nor are separate or alternative embodimentsmutually exclusive of other embodiments. Moreover, various features aredescribed which may be exhibited by some embodiments and not by others.Similarly, various requirements are described which may be requirementsfor some embodiments but not other embodiments.

Broadly, embodiments of the present invention disclose techniques forsearch and identification of objects on an image (hereinafter “thedisclosed techniques”). The search and identification of objects may bebased on a structural description.

A flexible document structure, which is also referred to herein as a“structural description” or “flexible structural description”, maycomprise the description of spatial and parametric characteristics ofdocument elements, and the logical connections between documentelements.

In one embodiment, there may be evaluation of correspondence of thesearch result to the structural description. Numbers from 0 to 1 areused for the evaluation. The accuracy of evaluation may be 10⁻⁵ (ten tothe power of minus five). In one embodiment the value equal to 1 meansthe absolute correspondence of the obtained result to the description.If the estimate differs from zero, the application of flexiblestructural description also comprises the stage of forming blockregions, i.e. evaluation of the arrangement of the required fields onthe basis of the information about the obtained objects.

The methods disclosed herein may be used in the recognition of datainput forms, containing typographical and hand-written texts as well asa set of special text-marks for document navigation.

The term “documents” as used herein is to be interpreted broadly toinclude inquiry lists, questionnaires, bank documents with rigid orarbitrary arrangement of data fields, and the like.

The disclosed techniques may be used for recognition of predefined formobjects contained in an electronic graphical image.

The disclosed techniques may include preliminarily assigning a documentstructure to an image being processed. Preliminary assignment of thedocument structure may comprise setting a description of the document'slogical structure in the form of interdependences of spatial andparametric characteristics of elements, algorithms of obtaining theparameters of the search for each element, methods of identifying theobtained elements, methods of decreasing the number of obtained variantsof an element, acceleration of the search for the best variant.

The disclosed techniques may include a method of searching andrecognizing the elements (fields or field fragments) of a document on agraphical (bit-mapped) image based on a predefined logical structure ofthe document in the form of a structural description, algorithms ofobtaining the parameters of the search for each element, methods ofidentifying the obtained elements, methods of decreasing the number ofobtained variants of an element, acceleration of the search for the bestvariant.

In one embodiment searching for elements with the help of a flexiblestructural description is performed sequentially in the order in whichthey are described in the flexible structural description, top-downthrough the “tree” (hierarchy) of elements, in accordance with thelogical structure of the document description. For each element in theassigned search area, several variants of image objects or sets of imageobjects corresponding to the description of the element in thestructural description may be found. Various obtained variants ofobjects are considered to be the variants of the position of the elementon the image. An estimate of the degree of correspondence of the variantto the element description is assigned to each obtained variant (i.e.the estimate of the quality of the variant).

In one embodiment, the accuracy of the obtained position of the objectdetermines the accuracy of obtaining the positions of objects describedfurther in the description relative to this object. Searching for thenext dependent object is performed separately for each obtained variantof the current object. Therefore, the variants of objects obtained onthe image comprise a hierarchical tree is considerable more branchedthan the hierarchical tree of elements in a structural description.

If an element or an object is compound, i.e. the element is a group ofelements comprising several parts, then the whole group also representsan element, which requires generating several possible variants, thenumber of which corresponds to the number of complete chains of groupsub-elements (dependent elements of a lower level). The chain isconsidered complete if all its obtained sub-elements (elements of alower level) have sufficient quality. The total estimate of the qualityof a variant of a compound element is calculated by multiplying theestimates of the quality of element variants forming the compoundelement. A flexible structural description as a whole also represents acompound element. Therefore, the quality of the correspondence of thevariant to the flexible structural description is determined bymultiplying the quality of its elements.

Application of a flexible structural description comprises searching forthe best complete branch in the whole tree of variants, i.e. the branchthat include all the elements, from first to last. A general solution ofsuch a task implies taking into consideration all the possiblecombinations of hypotheses for all elements, construction of a totalmultitude of complete branches and selecting the best among them.However, in practice, such a solution requires too many resources, andis therefore impractical. Moreover, an abrupt increase in the number ofvariants taken into consideration is possible, caused by an increase inthe number of elements and a lack of rigid restrictions on the searcharea and element parameters.

To limit the time required to analyze the variants, one of severalmethods of decreasing the volume is used.

Each element gets the maximum allowed number of acceptable variants,rated in the order of decreasing quality. These variants will be used inthe further search, i.e. when searching for the next element. Anyvariants beyond this number will be discarded. Usually this number is 5(five) for simple elements and 1 (one) for compound elements. This meansthat, if 15 variants are obtained for a simple element in the assignedsearch area, five variants with the best quality rating will beselected. Other 10 chains of variants will not be complete and will notbe taken into consideration. A compound element is identified with agreater quality rating than a simple element, because the quality ofidentification is determined not only by multiplying the quality ratingsof the constituent simple elements, but also by several additional(mainly qualitative) characteristics, such as mutual arrangement, objectsize, correspondence to the conditions of mutual arrangement severalelements, and so on.

Since a compound element is identified with a greater quality ratingthan a simple element, its best variant usually turns out to beaccurate.

The process of searching for objects almost always includes generatingseveral incomplete chains of variants of obtained objects and,therefore, several directions of further search. Using an algorithm of“broad searching” performs a search for the best hypothesis, i.e. thesearch is always directed through the chain of variants that has thebest quality rating at the current step, regardless of the length of thechain. For example, if in a flexible structural description of 30elements 2 chains are obtained during search, one of which consists of30 elements with the quality rating of 0.89 and the other chain has 2elements with the quality rating of 0.92, then the second chain will bepursued until its total quality becomes lower than that of the firstchain.

The following rule of quality optimization is used for compoundelements: if an ideal complete chain for this element is obtained, i.e.the quality of the obtained chain equals 1, other variants ofsub-elements composition of this compound element are not taken intoconsideration.

Moreover, the maximum number of variants for every element in the entirehypothesis tree is restricted to 1000.

A set of spatial and parametric characteristics sufficient for searchfor and identification of an element is used to describe elements of adocument of a non-fixed format. A structural description consists of adescription of spatial and/or parametric characteristics of the element,and a description of its logical connections with other elements.

A good example of a document with a flexible or non-fixed format isshown in FIG. 6), where the regular elements are the fields for“Abstract”, “Inventors:”, “Appl. No.:” and etc, and variable elementsare the content of the fields

A flexible structural description may also additionally include all orsome of the following conditions. The logical structure of a document isrepresented as a sequence of elements connected mainly by hierarchicaldependences; an algorithm of determining the search parameters is set,spatial characteristics for searching for each element are specified,parametric characteristics of the searching for each element are set,the set of parameters for identifying a compound element on the basis ofthe aggregate of components is set, and an algorithm of estimating thequality of an obtained variant of an element is set.

A flexible structural description may also additionally include aseparate brief structural description for determining the correctspatial orientation of the image.

A flexible structural description may also additionally include aseparate brief structural description for determining the document typeand selecting the corresponding comprehensive document description fromseveral possible descriptions. A comprehensive description is createdfor each document type. If a document type does not have a briefdescription, then the comprehensive description of the document is usedfor selecting its type.

The structure of element connection is mainly realized as a hierarchicalstructure.

In one embodiment, the method of search and recognition (identification)of elements (fields) on an image (101) of non-fixed format correspondingto a form, comprises the following steps:

Searching and identifying (including recognition) the elements of adocument with non-fixed format comprises at least the followingpreliminary actions (102).

(1) Performing a recognition operation comprising:

-   -   (a) Revision or analysis of the entire document image (202).    -   (b) Allocation of a position (spatial location) for the detected        objects or object fragments (203).    -   (c) Performing an initial classification of the allocated        objects according to the set of predefined types and selecting        the text objects, where the text must be recognized (204).    -   (d) Recognition of all or a part of text objects, where each        object is recognized partially or entirely (205).

In one embodiment, to speed up the processing, recognition of textobjects is performed to a minimum degree that is sufficient foridentifying the document structure and other elements of the form (206).

(2) A separate structural description is set to detect the spatialorientation of an object (103). Such a description usually contains abrief set of structural elements which can be easily recognized on adocument (form). Orientation is accepted as correct if the elements ofthe structural description coincide with the elements on the image withthe best quality estimate.

(3) A corresponding separate brief description is set for quickdetection of the type of a recognized document and selecting thecomprehensive (main) description of the document type from severalpossible descriptions (104). A comprehensive description is created foreach document type. If any document type does not have a briefdescription, then the comprehensive description of the document is usedfor selecting its type, and the selection of the document type isperformed by comparing the quality estimates of the used (brief orcomprehensive) descriptions of different types.

(4) Performing a searching operation (105) for elements of the formbased on a structural description, including:

-   -   (a) Choosing an element or the next element (302) in the        structural description (starting from the first one).    -   (b) Calculating or obtaining a predefined algorithm (303) for        determining the search parameters or constraints.    -   (c) Performing a search for an element (304), comprising at        least the following operations:    -   (d) Searching by using the spatial characteristics of the search        area such as, for example, half-plane, rectangle, circle,        polygon and others, or any combinations thereof;    -   (e) Searching by using the parametric characteristics of an        element (the type of element);    -   (f) Searching with the help of the results of preliminary text        recognition;    -   (g) Searching by using the spatial characteristics of an        element, represented as absolute coordinates and/or coordinates        relative to the other elements (located higher in the tree). The        coordinates may be specified as exact values or as an interval.    -   (h) Calculating the quality of correspondence of the obtained        variant to the description of the required element.    -   (i) Testing (305) the obtained variants of the object (401)        comprises the following operations.    -   (j) Identifying the obtained element variant (402);    -   (il) Calculating the quality of the identification of the        element (403);    -   (m) Analyzing the results of testing the hypotheses (404) about        the presence and completeness of the composition of the element        and the types of composite parts, analyzing of the        correspondence of a compound element to the hypothesis about the        type of the element;    -   (n) Calculating the total reliability of the obtained variant        (405).    -   (o) Optimization (306) of revision of element combination        variants comprises    -   (p) Assigning to each type of the element several variants with        the best quality rating, which are kept for further analysis;    -   (q) Searching for the best variant of a compound element, taking        into account the best total quality estimate of composite parts,        regardless of their number;    -   (r) Revision of the quality estimates of the variants which were        discarded earlier in order to find any quality estimates which        would be higher than the current one.    -   (s) If the total quality estimate is lower than the predefined        level, searching for the next variant of the same element and        calculating its total quality estimate are performed.    -   (t) If the total quality estimate is higher than the predefined        level, searching for the next element is performed.    -   (u) The variant with the maximum total quality estimate is        selected.    -   (v) Searching for the best variant of a compound element is        performed, taking into account the best total quality estimate        of accountable composite parts, regardless of their number.

The quality of a variant as supposed herein is the estimation whichindicates the degree of correspondence of the obtained variant to thepresent element (its properties and search constraints). The numericalconstituent of the quality of a variant is a number ranging from 0 to 1.The quality of a hypothesis for a compound element is calculated bymultiplying the quality estimates of the hypotheses of all thesub-elements thereof.

The quality of a variant is a result of multiplication of the quality ofthe element, assigned at the stage of specification of the structuraldescription during the specification of the element type, and thequality of the element (object), variant is calculated at the stage ofthe search. The total quality of the variant is calculated as a productof quality ratings of all interdependent composing elements in thechain, from the first element in the structural description to thecurrent element.

For optional elements i.e. such elements, which may be missing on adocument, a “zero” variant of an element is used, if the element has notbeen detected. A “zero” variant supposes that the required object ismissing in the search area. A “zero” variant is formed, if no objectsare detected corresponding to the optional element and having thequality estimate which is greater than the quality of the zero variant.If the zero variant is selected as the most appropriate, the process isstarted of searching and identifying the next element in the list(including the elements which depend on the element which has not beenobtained), or analyzing one of the earlier rejected variants of the sameelement or another element, simultaneously taking appropriate measuresto avoid creating an infinite loop in the process.

If no objects are detected corresponding to the optional element, theuse of the flexible description is not stopped. Instead, a zero variantis generated which gains the quality value predefined by the user in thedescription of this optional element.

Creation of the flexible structural description uses the following maintypes of elements conventionally divided into the following: simpleelement which do not contain other elements: Static Text, Separator,White field, Barcode, Text String, Text Fragment, Set of objects, Date,Phone Number, Currency, and Table, and compound elements—Group, and someother types.

Static text, as supposed herein, is an element of structural descriptiondescribing a text with the known meaning. The text may consist of oneword, of several words, or of an entire paragraph. “Several words”differs from “a word” by the presence of at least one blank space oranother inter-word separator, depending on the language, for example, afull stop, a comma, a colon, or any other punctuation mark. Severalwords may take up several text strings.

Separator, as supposed herein, is an element representing a vertical orhorizontal graphical object between other objects. A solid line or adotted line can represent a separator, for example.

White field, as supposed herein, is an element of descriptionrepresenting a rectangular region of an image that does not contain anyobjects within it.

Barcode, as supposed herein, is an element of flexible descriptionrepresenting a line drawing that codes numerical information.

Text string, as supposed herein, is an element representing a sequenceof characters located on a single line one after another. Characterstrings can consist of text objects, for example, words, or of fragmentsof text objects.

Text fragment, as supposed herein, is an element representing anaggregate of text objects.

Set of objects (of the specified type), as supposed herein, is anelement representing an aggregate of different types of objects on animage, where each object meets the search constraints.

Date as supposed herein, is an element representing a date.

Telephone number, as supposed herein, is an element representing atelephone number which may be accompanied a by prefix (“tel.”, “hometel.”, etc.) and by a code of the city/region, which is separated fromthe number by brackets.

Currency, as supposed herein, is an element of description representingmoney sums, where the name of the currency can be used as the prefix.

Table, as supposed herein, is an element of flexible descriptionrepresenting data in the form of a table.

Compound element (element group), as supposed herein, is an aggregate ofseveral elements (sub-elements). Sub-elements may be simple or compound.

Compound Elements are Used for:

joining elements into a group. Each of these compound elements maycontain smaller compound elements which search for smaller fragments ofthe element;

providing the logical hierarchy of elements for better navigationthrough the structural description;

reducing the number of possible variants of the element in order tospeed up the search for the resulting variant. Joining elements into acompound element allows to analyze this set of sub-elements as a singleentity which has its own complete variant (consisting of the variants ofthe sub-elements) and a total estimate of reliability of the entiregroup. Revision of possible combinations of variants of the sub-elementsis performed within the group, and only a predefined number of the bestvariants in the group take part in the further analysis and search forthe next elements. The number of the best variants of a compound elementwhich take part in further searching is usually 1;

specifying restrictions of the search area which are common for all thesub-elements. The search area of a certain sub-element in this case iscalculated as the intersection of the search area set for thesub-element itself and the search area of the group which contains thissub-element.

FIG. 6 of the drawings shows hardware 600 that may be used to implementthe disclosed techniques, in accordance with one embodiment of thedisclosure. Referring to FIG. 6, the hardware 600 typically includes atleast one processor 602 coupled to a memory 604. The processor 602 mayrepresent one or more processors (e.g. microprocessors), and the memory604 may represent random access memory (RAM) devices comprising a mainstorage of the hardware 600, as well as any supplemental levels ofmemory, e.g., cache memories, non-volatile or back-up memories (e.g.programmable or flash memories), read-only memories, etc. In addition,the memory 604 may be considered to include memory storage physicallylocated elsewhere in the hardware 600, e.g. any cache memory in theprocessor 602 as well as any storage capacity used as a virtual memory,e.g., as stored on a mass storage device 610.

The hardware 600 also typically receives a number of inputs and outputsfor communicating information externally. For interface with a user oroperator, the hardware 600 may include one or more user input devices606 (e.g., a keyboard, a mouse, imaging device, scanner, etc.) and a oneor more output devices 608 (e.g., a Liquid Crystal Display (LCD) panel,a sound playback device (speaker). To embody the present disclosure, thehardware 600 must include at least one touch screen device (for example,a touch screen), an interactive whiteboard or any other device whichallows the user to interact with a computer by touching areas on thescreen.

For additional storage, the hardware 600 may also include one or moremass storage devices 610, e.g., a floppy or other removable disk drive,a hard disk drive, a Direct Access Storage Device (DASD), an opticaldrive (e.g. a Compact Disk (CD) drive, a Digital Versatile Disk (DVD)drive, etc.) and/or a tape drive, among others. Furthermore, thehardware 600 may include an interface with one or more networks 612(e.g., a local area network (LAN), a wide area network (WAN), a wirelessnetwork, and/or the Internet among others) to permit the communicationof information with other computers coupled to the networks. It shouldbe appreciated that the hardware 600 typically includes suitable analogand/or digital interfaces between the processor 602 and each of thecomponents 604, 606, 608, and 612 as is well known in the art.

The hardware 600 operates under the control of an operating system 614,and executes various computer software applications, components,programs, objects, modules, etc. to implement the techniques describedabove. In particular, the computer software applications will includethe client dictionary application, in the case of the client user device102. Moreover, various applications, components, programs, objects,etc., collectively indicated by reference 616 in FIG. 6, may alsoexecute on one or more processors in another computer coupled to thehardware 600 via a network 612, e.g. in a distributed computingenvironment, whereby the processing required to implement the functionsof a computer program may be allocated to multiple computers over anetwork.

In general, the routines executed to implement the embodiments of thedisclosure may be implemented as part of an operating system or aspecific application, component, program, object, module or sequence ofinstructions referred to as “computer programs.” The computer programstypically comprise one or more instructions set at various times invarious memory and storage devices in a computer, and that, when readand executed by one or more processors in a computer, cause the computerto perform operations necessary to execute elements involving thevarious aspects of the disclosure. Moreover, while the disclosure hasbeen described in the context of fully functioning computers andcomputer systems, those skilled in the art will appreciate that thevarious embodiments of the disclosure are capable of being distributedas a program product in a variety of forms, and that the disclosureapplies equally regardless of the particular type of computer-readablemedia used to actually effect the distribution. Examples ofcomputer-readable media include but are not limited to recordable typemedia such as volatile and non-volatile memory devices, floppy and otherremovable disks, hard disk drives, optical disks (e.g., Compact DiskRead-Only Memory (CD-ROMs), Digital Versatile Disks (DVDs), flashmemory, etc.), among others. Another type of distribution may beimplemented as Internet downloads.

While certain exemplary embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative and not restrictive of the broad disclosure and thatthis disclosure is not limited to the specific constructions andarrangements shown and described, since various other modifications mayoccur to those ordinarily skilled in the art upon studying thisdisclosure. In an area of technology such as this, where growth is fastand further advancements are not easily foreseen, the disclosedembodiments may be readily modifiable in arrangement and detail asfacilitated by enabling technological advancements without departingfrom the principals of the present disclosure.

In the foregoing specification, specific embodiments of the presentdisclosure have been described. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the present disclosure as set forthin the claims below. Accordingly, the specification and figures are tobe regarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofpresent disclosure. The benefits, advantages, solutions to problems, andany element(s) that may cause any benefit, advantage, or solution tooccur or become more pronounced are not to be construed as a critical,required, or essential features or elements of any or all the claims.The disclosure is defined solely by the appended claims including anyamendments made during the pendency of this application and allequivalents of those claims as issued.

1. A method of searching for elements of a form, comprising: performinga recognition operation comprising: detecting objects on an image forthe form; allocating a position for each object; selecting text objects,where the text must be recognized, and recognizing the text objects; andperforming a searching operation for elements of the form based on astructural description, said searching operation comprising: selectingan element in the structural description for the searching operation;determining an algorithm for determining search constraints for thesearching operation; searching for the element; testing variants for theelement obtained through said searching; optimizing analysis of variantsof combinations of elements; wherein searching for the elementcomprises: searching with the use of spatial characteristics of a searcharea for the element; searching with the use of the parametriccharacteristics of the element; searching with use of the absoluteand/or relative spatial characteristics of the element—represented asexact values and/or as intervals; searching with the use of the resultsof preliminary text recognition, and testing variants comprises:identifying the obtained variant of the element; estimating the qualityof the identification of the element; analyzing the results of testingthe hypotheses about the presence, completeness of composition, andtypes of composite parts, analyzing their correspondence to thehypothesis about the type in the case of a compound element; estimatingthe total reliability of the obtained variant, optimization of theanalysis of variants of combinations of elements, comprising: assigninga number of variants with the best quality ratings which will be keptfor further analysis to each type of the element; searching for the bestvariant of the compound element, taking into account the best totalquality of its accountable composite parts, regardless of their number,analyzing the quality estimates of earlier rejected variants in order toobtain quality estimates higher than the current estimate.
 2. A methodof searching, as recited in claim 1, where the orientation of the imageis determined.
 3. A method of searching, as recited in claim 2, whereall or a part of elements of the structural description are used todetermine the correct orientation of the image.
 4. A method ofsearching, as recited in claim 3, where an auxiliary description inbrief form is optionally assigned to determine the spatial orientationof the image.
 5. A method of searching, as recited in claim 3, where theorientation of the image whose objects of the description coincide withthe objects on the image with the maximal quality rating is accepted asthe correct orientation of the image.
 6. A method of searching, asrecited in claim 1, where the type of a document is selected fromseveral available types.
 7. A method of searching, as recited in claim6, where a separate brief structural description is optionally includedfor determining the document type and selecting the correspondingcomprehensive document description from several available descriptions.8. A method of searching, as recited in claim 7, where the type of thedocument which corresponds to the current image is selected on the basisof comparing the quality estimates of the used descriptions.
 9. A methodof searching, as recited in claim 1, where initially the first elementin the list is selected.
 10. A method of searching, as recited in claim1, where the spatial characteristics of an element including itsabsolute coordinates and/or relative coordinates are used.
 11. A methodof searching, as recited in claim 1, where the exact and/or intervalcharacteristics of an element are used.
 12. A method of searching, asrecited in claim 1, where the following spatial characteristics of thesearch area are also used: a half plane, a rectangle, a circle, apolygon, or a combination thereof.
 13. A method of searching, as recitedin claim 1, where the quality estimates of all earlier rejected variantsare analyzed after the estimation of the total quality rating of thevariant to select a variant with the best quality rating.
 14. A methodof searching, as recited in claim 1, where searching for the next objectis performed if there are no variants for the current element or thetotal quality rating is lower than the predefined level.
 15. A method ofsearching, as recited in claim 1, where revision of variants ofcombinations of the elements is considered complete if the total qualityestimate of the complete set of elements achieves the quality valueof
 1. 16. A method of searching, as recited in claim 1 where one tothree variants of a compound element which have the best qualityestimate are used for further analysis.
 17. A method of searching, asrecited in claim 1, where three to ten variants of a simple elementwhich have the best quality estimate are used for further analysis. 18.A method of searching, as recited in claims 1, where the program startssearching for an object corresponding to the next element of thestructural description, if no objects are detected in the region of theimage which is specified for the current element.
 19. A method ofsearching, as recited in claim 1, where a “zero” variant of an elementis used for optional elements, has not been detected.
 20. A method ofsearching, as recited in claim 1, where the orientation of the image isdetermined.
 21. A method of searching, as recited in claim 20, where allor a part of elements of the structural description are used todetermine the correct orientation of the image.
 22. A method ofsearching, as recited in claim 21, where an auxiliary brief descriptionis optionally specified to determine the spatial orientation of theimage.
 23. A method of searching, as recited in claim 21, where theorientation of the image whose objects of the description coincide withthe objects on the image with the maximal quality rating is accepted asthe correct orientation of the image.
 24. A method of searching, asrecited in claim 1, where the type of the document is selected fromseveral available types.
 25. A method of searching, as recited in claim24, where a separate brief structural description is optionally includedfor determining the document type and selecting the correspondingcomprehensive document description from several available descriptions.26. A method of searching, as recited in claim 25, where the type of thedocument which corresponds to the current image is selected on the basisof comparing the quality estimates of the used descriptions.
 27. Amethod of searching, as recited in claim 1, where the recognition isperformed to a predefined minimum degree that is sufficient foridentifying a document structure for the form.
 28. A system, comprising:a processor; and a memory coupled to the processor; wherein the memorystores instructions which when executed by the processor causes thesystem to perform a method of searching for elements of a form,comprising: performing a recognition operation comprising: detectingobjects on an image for the form; allocating a position for each object;selecting text objects, where the text must be recognized, andrecognizing the text objects; and performing a searching operation forelements of the form based on a structural description, said searchingoperation comprising: selecting an element in the structural descriptionfor the searching operation; determining an algorithm for determiningsearch constraints for the searching operation; searching for theelement; testing variants for the element obtained through saidsearching; optimizing analysis of variants of combinations of elements;wherein searching for the element comprises: searching with the use ofspatial characteristics of a search area for the element; searching withthe use of the parametric characteristics of the element; searching withuse of the absolute and/or relative spatial characteristics of theelement—represented as exact values and/or as intervals; searching withthe use of the results of preliminary text recognition, and testingvariants comprises: identifying the obtained variant of the element;estimating the quality of the identification of the element; analyzingthe results of testing the hypotheses about the presence, completenessof composition, and types of composite parts, analyzing theircorrespondence to the hypothesis about the type in the case of acompound element; estimating the total reliability of the obtainedvariant, optimization of the analysis of variants of combinations ofelements, comprising: assigning a number of variants with the bestquality ratings which will be kept for further analysis to each type ofthe element; searching for the best variant of the compound element,taking into account the best total quality of its accountable compositeparts, regardless of their number, analyzing the quality estimates ofearlier rejected variants in order to obtain quality estimates higherthan the current estimate.
 29. The system of as recited in claim 28,where the recognition is performed to a predefined minimum degree thatis sufficient for identifying the a document structure for the form. 30.A computer-readable medium having stored thereon a sequence ofinstructions which when executed by a system, causes the system toperform a method of searching for elements of a form, comprising:performing a recognition operation comprising: detecting objects on animage for the form; allocating a position for each object; selectingtext objects, where the text must be recognized, and recognizing thetext objects; and performing a searching operation for elements of theform based on a structural description, said searching operationcomprising: selecting an element in the structural description for thesearching operation; determining an algorithm for determining searchconstraints for the searching operation; searching for the element;testing variants for the element obtained through said searching;optimizing analysis of variants of combinations of elements; whereinsearching for the element comprises: searching with the use of spatialcharacteristics of a search area for the element; searching with the useof the parametric characteristics of the element; searching with use ofthe absolute and/or relative spatial characteristics of theelement—represented as exact values and/or as intervals; searching withthe use of the results of preliminary text recognition, and testingvariants comprises: identifying the obtained variant of the element;estimating the quality of the identification of the element; analyzingthe results of testing the hypotheses about the presence, completenessof composition, and types of composite parts, analyzing theircorrespondence to the hypothesis about the type in the case of acompound element; estimating the total reliability of the obtainedvariant, optimization of the analysis of variants of combinations ofelements, comprising: assigning a number of variants with the bestquality ratings which will be kept for further analysis to each type ofthe element; searching for the best variant of the compound element,taking into account the best total quality of its accountable compositeparts, regardless of their number, analyzing the quality estimates ofearlier rejected variants in order to obtain quality estimates higherthan the current estimate.
 31. The computer-readable medium as recitedin claim 30, where the recognition is performed to a predefined minimumdegree that is sufficient for identifying a document structure for theform.